Paper pulp screen plates and support means for the same



March l1, 1952 v. JOHNSON 2,588,533

PAPER PULP SCREENLPLATES AND SUPPORT MEANS FR THE SAME Filed Nov. 29, 1946/? :[7] 5 1 2 Sil-IETS--SHEET l lmnmmmum m m 'T' 'TL' m c mmnmrlnum ff J 4 J5 ,w

2 wfuufnwnfffm U 0 w /20 j? mnmmmmur f2 d LLJIMUWHMLM# o f m i, m mi l l L I IA! ILI J5 /1 JJ j /0/ 2,588,533 PAPERV PULP SCREEN-PLATES AND SUPPORT MEANS PoR THE SAME 2'- sHEETs-SHEET 2 March ll, 1952 v. JOHNSON Filed Nov. 29, 1946 Patented Mar. 11, 1952 UNITED sra'rss oFFlcE Victor Johnson, Providence, R. I.

Application November 29, 1946, Serial No. 713,188

6 Claims. 1

This invention relates to improvements in th method ofmounting of paper pulp screens and more in particular to a new and useful improvement in means of securely retaining the screenplates to the frame.

One of the objects of the invention is to provide positive means to prevent the continuously vibrating screen-plates from getting loose from the frame in which they are held.

A further object is to provide a device of the character described in which the screen plates have a plurality of slots of substantially oblong cross sections the areas of which are minimum toward the top of the plates and are gradually increasing toward the bottom inducing maximum velocity of the flow of the pulp at the top regions of the slots accompanied by minimum pressure head and corresponding suction eie-ct so that the flow of the pulp through the slots is enhanced and their clogging is inhibited.

Another object is to provide a device of the type set forth in which the screen plates are clamped to support members associated with the frame by vertically reciprocable followers, guided by rails and mounted in housings, embedded in the frame, the followers coacting with oscillatable clamping members secured for limited relative motion to the followers by a xed pin and coacting elongated slot.

Another object is to employ a resilient gasket between the support members and the screen plate for sealingly clamping the former to the latter and equalizing the pressures of the individual clamping means to prevent breakage and distortion.

Another object of the invention is to provide paper pulp screens which may be readily replaced.

Still another object of the invention is to provide a paper pulp screen with new and simple means forsecurely fastening the screens to the frame.

Yet another object of the invention is to provide a paper pulp screen in which the screens are held in position by specially designed clamps which are swivelly mounted in adjustable followers.

Another object of the invention is the improved construction and method of mounting of the paper pulp screens.

Further objects of the invention are to provide a device of the class set forth which is simple in its construction and arrangements, efficient in its use, readily installed and inexpensive to manufacture.

To the accomplishment of these and such other v erence designate corresponding Aparts throughout the several views,

Figure 1 is a top plan view o'f a series of paper pulp screens mounted in a frame and embodying the invention.

Figure 2 is a horizontal cross section through the screen-plate and the stiifyening bars, taken on line 2--2 in Figure l.

Figure 3 is a sectional View through the side of the frame on line 3--3 in Figure l.

Figure 4 is a vertical sectional view takin on line 4 4 in Figure 1.

Figure 5 is a vertical sectional view taken on line 5--5 in Figure 1.

Figure 6 is a fragmentary top view of Figure 4.

Figure 7 is a horizontal sectional view on line l-'I in Figure 4.

Figure 8 is a horizontal sectional view taken on line 8-3 in Figure 4.

Referring now to the drawings, I0 represents the frame which may be made of wood or other suitable material forming the substantially vertical sides of a container. The paper pulp screen Il comprises of a series of screen-plates I2 mounted in a manner as best shown in Figure 1 of the drawings.

These screen-plates I2 as shown in Figure 2 comprise a plurality of elongated, rectangular plates I3, preferably of bronze or other nonrusting material, having a series of transverse slotted openings I4, the lower ends of which are flared outwardly and indicated by the numeral I5. Openings I4' have substantially oblong cross sections the smallest areas of which are toward the top regions of the slots, the areas gradually increasing toward the bottom.

Secured to the underside of the elongated edges of said plates I3 by means of screws I6, or otherwise, are outwardly extending bars I'I, the top' face I8 of the exposed portion I9 thereof being sloped up and outwardly to form a seat` for the holding-down bar or beam 2U.

Rectangular stiifening bars 2| of substantially the same height as bars I1 are secured to the ends ofthe plates i3 as shown in Figure 3.

The aforesaid holding-down bar 20 comprises a substantially T-shaped, elongated member having a head 22, the undersides 23 of which -conform to the sloped faces I8 of bars Il of the plates I3, as best shown in Figures 4 and 5.

The reinforcing center rib 24 of bar 2B, when in position, extends downwardly into an elongated U-shaped member 25 the ends of which having ond-plates 25 which are secured to the inner sides of frame I by means `of bolt connections 2l, as best shown in Figures 3 and 4.

Each leg of said U-shaped member 25 is provided with an outwardly extending horizontal flange 2S which is adapted to support the elongated edge of the screen-plate I2.

When in position, the screen-plates I2 rest on a gasket 29 which in turn rests on the flanges 28 of the U-shaped member 25.

As will be noted in Figures 4 and 5, the ends of the T-shaped holding-down bars 20 are securely held in position by clamping members 3D swivelly mounted in a follower 3| ywhich is mounted for up or down movement in the housing 32 by means of a screw 33.

As shown in dot and dash lines in Figure 5, the clamping member 3G may be swung toward the center of the frame after the follower 3! has been moved upwardly by means of the screw 33.

The clamping mechanism 34 for the screenplates I2 is preferably embedded in the sides 35 of the frame I0 in a metallic, rust-proof housing 32 in which is slidably mounted the follower 3l which may be raised or lowered by the screw 33, to release or tighten the ends 36 of the holding-down bar 29 by means of the clamping member 3G.

The aforesaid housing 32 is recessed into the inner face 31 of the sides 35 of frame I9 and secured thereto by screws 38 as shown, or otherwise.

The rectangular cavity 39 of housing 32 is pro- The follower 3| comprises a substantially rectangular block having vertically disposed slotted ends 4| adapted to slidingly engage at each side thereof the rails 49 of the housing 32.

Centrally disposed at the top of said follower is a cylindrical socket 42 into which fits the lower shank portion 43 of screw 33. This shank portion 43 is provided with a horizontally djsposed, semi-circular groove 44 which corresponds to the curvature of the shank 45 of the retaining screw 45 shown in Figures 4 and '7.

It is by means of this retaining screw 46 that the screw 33 is rotatably retained in the follower Si at the same time permitting the follower 3| to be raised or lowered when screw 33 is being turned in said housing in clockwise or counterclockwise direction respectively.

The said follower 3| is provided with a central rectangular cavity 41 which extends rearwardlysufficiently to receive the male portion of a hinge knuckle 49 of the clamping member 3U.

The hinge knuckle 49 is provided with a vertically disposed oblong slot 5| in .which freely operates the hinge-pin 50, the ends of which are secured in the follower 3|, thereby permitting the lowermost end of the clamping member 30 to be disengaged from its frictional hold on top if tleend of the holding-down bar 20 (Figures Adjacent the hinge-knuckle 49 of the clamping member 33 is an outwardly inclined follower supporting surface 52 which cooperates with the inclined bottom portion 53 of the follower 3| when in clamped position.

The hinge-knuckle 49 and vertically disposed slot 5I cooperate with the hinge pin 50 and follower supporting surface 52 to form aligning means for keeping the clamping member vertically aligned when in the clamping position.

The function of the above described arrangement will be readily understood by referring to Figures l, 4 and 5 inclusive.

The U-shaped members 25, preferably of non rusting material, are secured to the inner sides of the frame I6 after which a gasket 29 is placed on the top flanges 28. The screen-'plates I2 are then placed on top of the gasket 23 after which the holding-down bars 29 are properly placed between the screen-plates i2.

The clamping members 39 mounted in the inner sides of the frame I0 are thence swung into the position as shown in full lines in Figures 4 and 5, after which the clamping screw 33 is turned in clockwise direction until the inclined bottom portion 53 of the follower 3| engages the inclined portion 52 of the clamping member 30.

The lowermost portion 54 of the clamping member 3|] now contacts one of the two ends of the upper face 55 of the head 22 of the holdingdown bar 20 and by tightening the clamping screw 33, the holding-down bar 20 forces the screen plates I 2 against the gasket 29 and the ilanges of the U-shaped member 25 thereby providing a leak-proof joint between the adjoining screen-plates.

It will be noted, that the U-shaped members 25 and the housing 32 for the clamping mechanism 34 are permanently secured to the interiorsides of the frame ifi, but the screen-platesA I2 are readily removable by merely raising the fol-f lower 3| including the clamping member 30 by' means of the screw 33.

After the screen-plates I2 and the holdingdown bars 25 are properly placed and securely held in position by means of the clamping mechanism 34 the upper surfaces 55 of the screenplates I2 and the holding-down bars 29 will be smooth and even, thereby providing a smooth passageway for the pulp stock.

The screen plates having downwardly iia 1ed" out slots Ill-I5 provide for enhanced flow of the pulp through the slots. At the top regions of the slots their cross sectional area is minimum hence' the velocity of the ow maximum and the pressure head minimum, according to Bernoullis theorem. The low pressure head induces a suction effect which helps the iiow of pulp through the slots, inhibits their clogging.

Underneath the screen-plates is arranged machinery (not shown) for producing a downward suction which pulls the pulp down through the slotted openings or slits I4 of the screen-plates I2 and also gives an upward pressure, which 1 forces away any dirt covering the slits, this operation is being given additional help by the effect of flared-out slots 5.

It is believed that this invention provides su` perior screen plates and their fastenings to retain their original position, although, as is well known in the art, they are subject to continuous vibration.

From the foregoing description taken in connection with the accompanying drawings, the

.' construction, of the device and the method of operation will be readily apparent to those skilled in the art to which the invention appertains, and while describing the principle of operation of the invention together with the device which is now considered to be the best embodiment thereof, it is to be understood that various changes in the form, proportion and the minor details of ccnstruction may be resorted to without departing from the principle or sacrificing any of the advantages of the invention as defined in the appended claims.

I claim:

1. A paper pulp screen comprising a frame having a plurality of screen-plates therein, said screen-plates having a plurality of slots substantially oblong cross section the areas of which are minimum toward the top of said plates and are gradually increasing' toi-'ard the bottom thereof inducing maximum velocity of the flow of the pulp at the top regions of the slots accompanied by minimum pressure head and corresponding suction effect whereby the flow of the pulp through said slots is enhanced and their clogging is inhibited; transversely spaced U-shaped screen-plate supporting members secured to the inner sides of said frame; the upper ends of said U-shaped members provided with outwardly extending, horizontal flanges adapted to support said screen-plates; the longitudinal edges of said screen-plates having outwardly extending, upwardly inclined cut-out portions; holding. down bars registering with said inclined cut-out portions; said holding down bars provided with a depending center-rib which penetrates, when assembled the U-shaped portion of said U-shaped members thereby serving as a guide for locating the screen-plates in the frame; a gasket between the screen-plates and the flanges of the U-shaped members; clamping mechanisms adapted to bear against the upper ends of said holding down bar and securely tighten the screen-plates against the U-shaped members; said clamping mechanisms embedded in the vertical sides of said frame and in vertical alignment with said U-shaped members; said clamping mechanisms comprising a clamp housing having a pair of oppositely spaced vertical rails adapted to slidably engage a follower; a clamping member hingedly mounted to the underside of said follower; means to raise or lower said clamping member; said `follower and said clamping member are attached to each other by a pin secured to said follower; said clamping member having an elongated slot to freely accommodate said pin thereby permitting said clamping member to be swung outwardly.

2. In a paper pulp screening device having a frame forming the substantially vertical sides of a container and being provided with support members and clamping means for releasably atutaching screen plates thereto, said clamping means comprising a plurality of housings fastened to said frame each of said housings mounting a follower for vertical reciprocating movement, vertical rails, rigidly fixed to said housing for guiding said follower, a.vertical threaded spindle rotatably but axially substantially iixedly mounted in said'follower and coacting with a threaded aperture in said housing, a clamping member mounted thereon for laterally oscillating and limited reciprocating motions adapted to contact and bear down upon holding down bars holding said screen plates to said support members and inclined surfaces associated with said follower and with said clamping member, for keeping latter, when under pressure, vertically aligned with said follower.

3. In a paper pulp screening device having a frame forming the substantially vertical sides of a container and' `being provided with support members and clamping means for attaching screen plates thereto, gasket means for sealing between said support members and said screen plates, screening means associated with said screen plates, said screening means comprising a plurality of slots of substantially oblong cross sections the areas of which are minimum toward the top of said plates and are gradually increasing toward the bottom thereof inducing maximum velocity of the flow of the pulp at the top regions of the slots, accompanied by minimum pressure head and corresponding suction effect whereby the flow of the pulp through said slots is enhanced and their clogging is inhibited, said slots being parallel to each other and extending through the greater portion of one surface dimension of said plates and said clamping means comprising a plurality of housings fastened to said frame each of said housings mounting a follower for vertical reciprocating movement, vertical rails, rigidly fixed to said housings for guiding said follower, a vertical screen rotatably but axially substantially xedly mounted in said follower, and 'coacting witha threaded aperture in said housing, a clamping member mounted on said follower for laterally oscillating and limited relative reciprocating motions adapted to contact and bear down upon holding down bars holding said screen plates to said support member by means of said screw, and inclined surfaces associated with said follower and with said clamping member, for keeping latter when under pressure, vertically aligned with said follower, said aligning means including wedge-like coacting surfaces, a fixed pin and a cooperating :elongated slot for limited relative motion.

4. In a paper pulp screening device having a frame forming the substantially vertical sides of a container and being provided with support members and clamping means for attaching screen plates thereto, gasket means for sealing between said support members and said screen plates, screening means associated with said screen plates, said screen plates comprising a plurality of slots of substantially oblong cross sections the areas of which are minimum toward the top of said plates and are gradually increasing toward the bottom thereof inducing maximum velocity of the ow of the pulp at the top regions of the slots, accompanied by minimum pressure head and corresponding suction effect whereby the ow of the pulp through said slots is enhanced and their clogging is inhibited, said slots being parallel to each other and extending through the greater portion of one surface dimension of said plates and said clamping means comprising a plurality of housings mounted in apertures of said frame and iiush with the inside surfaces thereof, said housings being disposed in pairs, located opposite to each other, each of said housings mounting a follower for limited reciprocating movement, vertical rails, rigidly fixed to said housings for guiding said follower, a vertical threaded spindle rotatably but axially substantially xedly mounted in said follower and coacting with a threaded aperture in said housing, a clamping member mounted on the follower for laterally oscillating and limited relative recipro- '7 cating motions adapted to contact and bear down upon holding down bars holding said screen plates to said support members, and inclined surfaces associated with said follower and with said clamping member, for keeping latter, when under pressure, vertically aligned with said follower, said aligning means including wedge-like coacting surfaces, a, fixed pin and a cooperating elongated A slot for limited relative motion.

5. In a paper pulp screening device having a frame forming the substantially Vertical sides thereof and being provided with U-shaped supporting members adapted to support a plurality of transversely extending screen means having beveled edges adjacent the bottom of the frame the improvement in hold down means comprising a screen hold-down bar of substantially T- shaped cross section, the central leg of which lies between successive screen means and extends into the hollow of a U-shaped supporting member upon which the said screen means rest, beveled shoulders on the arms of said hold-down bar whose angle of bevel and bevel face dimensions are substantially equal to the beveled edges of the screen means and Whose thickness is such that a substantially smooth exterior surface is formed lwhen said bar is placed in cooperative position between the screen means, said holddown bar extending beyond the edges of the screen means and have a beveled bottom face eX- tending into a recess in the inner surface of the vertical side of the frame, and clamping means A including a follower member slidably mounted in clamping member in the recess against the screen hold-down bar to hold it in engagement with the screen means.

6. In a paper pulp screening device having a frame forming the substantially vertical sides thereof and provided with supporting members cooperating with a screen fastener bar to retain a pluralityof transversely extending screen means a clamping device comprising a follower member slidably mounted in a recess in the inner surface of the vertical sides of the container, a vertically extending rail on each side of said recess, a track in each corresponding side of the follower member adapted to engage and slide upon said rail, a clamping member pivotally mounted on said follower member and adapted to pivot into the recess between the follower member and a screen hold-down bar, said follower member and clamping member being of such dimensions that their exposed vertical face surfaces are substantially flush with the inner vertical surface of the sides and screw means in the vertical sides for slidably moving the follower member and clamping member in the recess and into engagement with the screen hold-down bar.

VICTOR JOHNSON.

REFERENCES CITED The following references are of record in the file of this patent:

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